Whats the difference between a pandemic and a seasonal outbreak of influenza?
A. Influenza pandemics are caused by the emergence of a virus that is “novel” (brand new) or radically different from flu viruses that circulated previously. Because people have no or little natural resistance to a new virus, and there is no readily-available vaccine, influenza pandemics often result in much more severe illness and death. “Seasonal” influenza outbreaks are caused by small changes in the common influenza viruses. Even though these viruses may change slightly from one flu season to another, many people have developed some immunity. Because similar viruses have circulated previously, vaccine is more readily available.
